The Creator/MarxBrothers' seventh film, released in 1937 and following closely in the same mold as their previous one, ''Film/ANightAtTheOpera''.

Judy Standish's (Maureen O'Sullivan) sanitarium is under threat of being taken over by unscrupulous businessman J.D. Morgan (Douglass Dumbrille), who wants to demolish it and expand his real estate monopoly. The only hope for Judy is if she can keep as a permanent patient the wealthy hypochondriac Mrs. Upjohn (Margaret Dumont), who will only stay if the sanitarium hires her favourite physician, Dr. Hugo Z. Hackenbush (Groucho Marx). Unfortunately for Mrs. Upjohn, Hackenbush is actually a confidence-trickstering veterinarian, who has to avoid being caught out by either Morgan's cronies, the Florida Medical Board or Mrs. Upjohn.

Meanwhile, Chico Marx and Harpo Marx play a sanitarium worker and a former jockey who have to save Hackenbush from a FemmeFatale employed by Morgan, while simultaneously trying to get the racehorse owned by Judy's fiancée Gil (Allan Jones) into race-winning condition.

Not to be confused with the 1976 Music/{{Queen}} album ''Music/ADayAtTheRaces'', which was named after the movie.
!! In addition to the usual tropes exhibited by the Creator/MarxBrothers, this film provides examples of:

* AccidentalMisnaming: Chico keeps pronouncing Groucho's character Hackenbush's name as "Hackannapuss".
* BerserkButton: Hi-Hat the horse utterly detests the main villain. This is used to advantage during the race.
* {{Blackface}}: The boys, evading the law, momentarily done blackface to hide among a bunch of stable hands. Harpo only paints half his face.
* BoyMeetsGirl:
-->''"I can't hide it any longer. I love you. It's the old story, boy meets girl -- [[RomeoAndJuliet Romeo and Juliet]] -- Minneapolis and St. Paul!"''
* CallBack: to ''Film/DuckSoup'' during the barn musical number, with the line "All God's children got swing." Previously it was "All God's children got ''guns.''"
* CoveredInMud: Harpo on the good guy's horse and another guy on the bad guy's horse are neck and neck to win when they take a spill into a big mud hole. Hurrying back into the race, the other guy comes in first...but a quick wash-off reveals it's on the good guy's horse.
* GrandeDame: Margaret Dumont again.
* HaveAGayOldTime: Groucho telling the female lead, "For you, I'd [[InterspeciesRomance make love to a crocodile]]." [[note]]At the time this movie was made (1937) ''make love'' was ''also'' being used in its modern, physical, sense and Groucho was not shy about his language.[[/note]]
* InducedHypochondria: The reason Hackenbush is so well trusted by Mrs Upjohn:
-->'''Mrs Upjohn:''' Why, I never knew a thing was wrong with me before I met him.
* LopsidedDichotomy:
-->"Either this man is dead, or my watch has stopped".
* MDEnvy: Groucho averts this by just practicing on humans anyway.
* MysteriousMiddleInitial: Dr. Hugo Z. Hackenbush.
* NonverbalMiscommunication: When Harpo tries to warn Chico about the frame job against Groucho. He gets it eventually.
* OneLiner
* OnlyOneName: Tony and Stuffy.
* ParlorGames: An OverlyLongGag has Stuffy spend an entire scene using charades to explain the villains' FrameUp plot to Tony.
* RealJokeName: Averted, Groucho Marx's character was going to be Doctor '''Quack'''enbush, but MGM's Legal department heard from an actual Dr. Quackenbush complaining, so the name was changed to Hackenbush.
* SpiritualSuccessor: The basic plot is markedly similar to the previous Creator/MarxBrothers film, ''Film/ANightAtTheOpera'', except with horse-racing instead of opera.
* SuspiciouslySimilarSubstitute: As with ''Film/ANightAtTheOpera'', Allan Jones fills in for Zeppo.
* ThisMeansWar: This is Hackenbush's first reaction when he hears the bugle from the racetrack--it got him out of the heated discussion he was having with Whitmore.
-->'''Hackenbush:''' So it's WAR! I'm off to the battlefield!
-->'''Mrs. Upjohn:''' No no! That's from the racetrack.
* WackyAmericansHaveWackyNames: Dr. Hugo Z. Hackenbush.